


'course I do

by ImagineYourself



Category: Marvel Cinematic Universe
Genre: Alpha/Beta/Omega Dynamics, Awkward First Times, Beta Bucky Barnes, Consensual Underage Sex, First Time, Fluff, Love Confessions, M/M, Mating Cycles/In Heat, Omega Steve, Pre-Serum Steve Rogers
Language: English
Status: Completed
Published: 2017-07-27
Updated: 2017-07-27
Packaged: 2018-12-07 20:22:01
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,008
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11631192
Author URL: https://archiveofourown.org/users/ImagineYourself/pseuds/ImagineYourself
Summary: Steve wasn't expecting his first heat so soon and Bucky only kind of knows how to help him. But even they can figure some things out together.. . .They were just teenagers with a penchant for getting into trouble and the last thing Steve wanted to worry about was mathematics. Instead, he was worrying about his shaking hands and the cold sweat he was breaking into, like he had a fever.





	'course I do

**Author's Note:**

> Steve is probably 16ish and Bucky is around 17 so they're not super underage or anything. 
> 
> I can't believe the first stucky fic I'm posting is this. Just put me in the sin bin already.

It was autumn and Steve couldn't quite shake the feeling that something was wrong. Well, a lot of things were wrong. It felt wrong that his mother had to take the night shifts at the hospital almost every night the past week and Steve was busy with schooling and trying to find a place to work during the day. They hadn't seen each other in days. But it was more than that, something felt wrong in the deepest part of Steve's gut, and he worried that if he was getting sick again, it was something truly terrible.

He found himself in the apartment he shared with his mother Friday evening, Bucky sitting on the couch next to him, and holding a notebook that he was trying to draw into but his hand was shaking too hard. Buck was wrapped up in whatever homework he was working on, only actually doing it because Steve had bugged him for hours so that he didn't have to do it over the weekend. They were just teenagers with a penchant for getting into trouble and the last thing Steve wanted to worry about was mathematics. Instead, he was worrying about his shaking hands and the cold sweat he was breaking into, like he had a fever.

“Hey, Buck?” he asked quietly, afraid of his voice shaking as well. The other boy didn't need to worry about him more than he already did.

“Yeah?” Bucky replied absently, chewing on the end of his pencil.

Steve took a breath and set his notebook down on the arm of the couch. “I think I'm gonna hit the hay.”

That got Bucky's attention and he looked over at Steve to ask, “You feelin' alright?”

“Yeah! Yeah, don't worry. Just, y'know, tired.”

“You sure?”

Steve tried to laugh it off and stood from the couch, a bout of dizziness hitting him hard for a few seconds. “You can stay, if you wanna. A nap might just do me good and I could still play some cards later.”

“You mean get all my pennies 'cause I swear nobody plays cards like you do.” Bucky was smiling but he still looked concerned when Steve glanced back at him, making his way towards the bedroom.

“Maybe you're just bad at it,” Steve teased from the doorway.

“Maybe you're just a punk,” Bucky called after him. “If you're not up in a couple hours I'm goin' home.”

“Finish your homework at least!” With that, Steve closed the bedroom door behind him and let out a breath. He was starting to feel really dizzy and he quickly made his way to the bed, collapsing onto it and groaning. He shifted around after a minute to get comfortable, then tried to set his internal clock to wake him in an hour or so, hoping he'd feel better then. His eyes were shut and his breathing slowed and . . .

Suddenly he shot awake, lying on his back with his limbs splayed out. The window was open a little bit, letting in some of the cool night air, but Steve was positively burning. He felt hot and sticky and wrestled with his shirt to pull it off before shoving his pants down his legs, throwing them both to the floor. It was marginally better, though he left his shorts on because Bucky was probably still there and he didn't want to seem indecent. It was an odd thought to have in his fever weakened state of mind, but it was there and Steve heaved a sigh, trying to get more comfortable to fall asleep again.

He must have eventually dozed off, because the next thing he knew he was on his stomach feeling sticky in all the right ways, half hard against the mattress, and he was pretty sure something was leaking out of his ass.

 _Shit._ His mom had told him this wouldn't happen until the next year. She'd told him enough that he knew what it was ( _heat_ ), what it meant ( _mate_ ), and who he needed to stay away from ( _alphas_ ). But he'd really been hoping she'd tell him more when the time came. As it was, he was on his own, and he had no idea what to do.

Just as he was beginning to think that everything was hopeless, a sudden thought bumped into his head, Bucky was still outside. Bucky might know what to do. He was smart, a beta, one of his sisters was an omega like Steve, though Steve had never told him the truth. He'd always skirted around it and Buck seemed to assume he was just a beta as well. Steve scrambled from the bed and to the door, throwing it open only to lean against the frame, chest heaving and body aching from just moving that far.

Bucky was still on the couch, laying out with a book on his lap, but he turned when Steve opened the door. “Stevie? You alright?” Trying to breathe, Steve shook his head. Bucky immediately set down his book and stood up. “What's wrong?”

“I—” Steve started, shaking. “Buck, I—I'm.” Bucky was looking at him with a concerned expression, patiently waiting. “I think I'm in heat.” The other boy took a slow step forward and stared at Steve with a strange mix of emotions. Steve was too fever riddled to read him properly, he just hoped for the best.

“You're an omega?” was all Bucky asked.

Steve nodded, shame coloring his cheeks more than the heat. “I never told you 'cause I thought it'd worry you, like you had to protect me. But I can protect myself.” He didn't really know what he was saying anymore, his forehead leaning on the door frame as he held himself upright, mostly.

“I know that, Stevie. It's okay. Did your mom tell you about it yet?” Buck's voice was soft and placating and he started making his way to Steve.

“Not a lot. Bucky, I'm scared.” Steve looked his best friend with wild eyes and a still heaving chest. “I wasn't supposed to . . . this shouldn't happen yet. Not 'til next year.”

Bucky had finally reached him and held his hands out before him like he was approaching a wild animal. Steve supposed there wasn't much difference. “Hey, it's okay. I can go get your ma from the hospital if you want. Or I could stay with you.”

Shaking his head hard, Steve muttered, “No, don't get my mom, they won't be happy if she has to leave early. But Bucky, you gotta go home and see your ma and sisters.”

“They can wait. Stevie I could help you, but you gotta tell me I can. You gotta say you want it.” Bucky's voice was strained and he was just a step from Steve, hands still up but shaking a little bit.

“Buck . . . I dunno. I-I mean to say, I know what you're asking but . . . you . . .”

“I'm serious, Steve. You don't want me, that's okay, I'll go get your mom and she can take care of you. But if you want me to stay, you gotta tell me now or I gotta go. You look . . . real good, Stevie.”

Steve could feel slick dripping slowly down his thighs. Bucky was looking at him with sincerity but he could see something else when he locked eyes with the other boy. “'course I want you to stay, Buck. But don't feel like you gotta, ain't nothing special about me.”

Bucky choked a laugh. One of his hands cupped Steve's cheek and tilted his face up. “You're Stevie, and that's pretty special.” Steve wanted to open his mouth and argue but Bucky took his lips in a kiss that stopped his breath. It was gentle until it wasn't and Steve's back was pressed against the door frame as he gasped, Bucky's hands on his hips and tugging their bodies closer together.

The simple feeling of Buck's warm hands, tight on his bare skin, was an instant relief to the shudders that were shaking Steve's smaller frame. “Bucky . . .”

“I wanted to do this for so long,” Bucky whispered, moving his hands to Steve's thighs and picking him up. Steve spindly arms wrapped around his shoulders to keep himself up as Bucky took them to his bed.

When Steve was laid out on his back, he asked, “What d'ya mean?” He frowned, his head fuzzy like he wasn't hearing right.

“Well, it's just . . .” Bucky's face turned pink and he settled next to Steve, propped up on an elbow. “I always thought we were both betas and, ya see, well, when I learned that two betas can mate I—I shouldn't be saying this. You're in heat, I gotta help you.”

Steve watched him shake his head with wide eyes, panting out little breaths as new, unexpected warmth coiled in his belly. “You mean that?” he whispered.

Bucky stared right back at him. He opened his mouth but nothing came out at first. Then he touched Steve's throat, trailed his fingers around the blond's neck. It made Steve let out a breathless little whine. “Stevie. Stevie . . . 'course I do. I mean it. But I didn't know we'd ever be like this.”

“I—Will you kiss me?” The soft request fell from Steve's trembling lips and there was no heavenly or divine power that could have stopped Bucky from shifting closer and pressing their mouths together.

With shaking fingers, Steve wrapped his hands around the back of Bucky's head, grasping at the strands of his hair. He moaned when he felt Bucky's palm on his chest. Steve wanted to hide his face in shame, cover his mouth to the indecent sounds he couldn't stop making. But Buck had him in a deep kiss, tonguing his way into Steve's mouth when the smaller boy tried to gasp in a breath.

“You okay, Stevie?” Bucky asked, pushing himself away but sliding his hand to rest on Steve's stomach.

Steve took a moment to gather air before he looked at Bucky and said, “Yeah. I just—I need—”

“Yeah? Whaddya need?”

Completely flushed from ears to neck, Steve reached out to try and push Bucky's hand closer to where he needed attention most. “I need your hands. Please, Buck, I feel so good when you—when you touch me.”

The breath that Bucky inhaled was audibly sharp, his brows drawing together as he looked down to where Steve's hands were wrapped around his wrist, trying to push him. He shut his eyes as he finally exhaled, trying to keep himself together.

“Relax, Stevie, I'll touch you all you want.” Bucky extricated his hand from the other boy's admittedly weak grip and sat himself up between Steve's legs. He then moved to pull his shirt over his head and tossed it to the floor along with the damp pants Steve had been wearing as a last ditch attempt to cover himself.

Steve wasn't looking when Bucky took him in, his skin a feast for Bucky's eyes. He still wasn't looking when Bucky ran his hands up the blond's thighs and leaned in to leave wet kisses on his abdomen. Finally, he looked down, shuddering and shaking with _heat_ and _need_ , when Bucky slid his tongue along Steve's dripping, pink cock.

The noise he made was less a moan than it was a purely animalistic groan.

Bucky paused and Steve almost let out a whine but he slapped a hand over his mouth before he could. His other hand was clutching sheets so tightly he thought they might rip. Toes curled and spine arched, he was all but begging for Bucky to continue.

But Bucky did not. Instead, he pulled himself up over Steve's prone body. Eyeing him with a serious expression, he managed to guide Steve's hand away to replace it with his lips. This kiss was different; it was crushing, desperate, and hungry.

“Please, please . . .” Steve was muttering as Bucky kissed his jaw, his throat. His nose buried into the side of Steve's neck, pressing against his scent gland and feeling the heat emanating from under Steve's skin.

Here was the best place to smell him, and Bucky knew it well after spending years with this kid. But the heady scent pouring off of Steve was like nothing Bucky had ever smelled on him. He couldn't get enough and ran his tongue over the spot, moaning from the intoxicating aroma.

“God, you smell so good, Stevie,” Bucky said quietly into his ear, just before catching the lobe and tugging it with his teeth. He received a whimper from Steve.

“Buck—y,” Steve whined, grappling with the beta's hair and pulling him so that they could kiss. It was wet and filthy and way off center and Steve was all but crying with need.

Reaching a hand down between Steve's legs, Bucky situated himself to Steve's side, letting him maintain the kiss. He swept his fingers along Steve's warm and clammy skin, down to tease at his hip, not quite touching his dick.

“Stop, stop,” Steve pleaded, his fingertips digging into Bucky's neck and shoulders.

Immediately, Bucky stopped moving. “Did I hurt you? What's wrong?” he asked quickly.

“No, Buck, keep touching me.” Steve's face was twisted with pain, his muscles shaking throughout his entire body. This just wasn't it. This wasn't _right_ yet.

“You told me to stop. What am I doin' wrong?” Bucky left his hand on Steve's hip, but leaned back from his face to look at him. “Whaddya want me to do, Stevie?”

Steve sucked in a breath and trembled, tossing his head around. He was too hot. He couldn't focus on anything but how hot and sticky he was and he just needed so much _more_. “Bucky. Bucky. Bucky, please. I—I need more. It hurts, Buck. I need _more_.” Steve finished on a whine, trying to pull Bucky on top of him.

Bucky just stopped, looking at him with wide eyes for a moment. When Steve met his gaze briefly, his pupils were expanded so wide, Bucky thought he could see a reflection of himself in there. He didn't know what to do. How could he—he wasn't an alpha. He hadn't ever been with—with a _boy_ , even though he'd certainly thought about Steve enough. And Steve was here in front of him, needing him, and Bucky had no idea what to do past necking and petting.

So he caught Steve in a kiss and took Steve's cock in hand, giving it a few experimental rubs. Steve cried out, his lithe little body squirming and writhing. Feeling a little more confident, Bucky stroked him faster, taking in stride the way Steve's hips were jerking up. Steve's knees lifted, his feet pressing into the bed.

“Yes, Bucky, please,” Steve whimpered. “I want you—need you in-inside me, _please_.”

'Oh,' Bucky thought, everything falling into place. He wanted to smack himself upside the head for being such an idiot this whole time. This wasn't just heavy petting, this wouldn't be over with just his hand on Steve's prick. This was a _heat_. He'd learned about this at some point, he knew.

Bucky did some maneuvering, getting his trousers off and one of Steve's thin legs over his shoulder, pressed up so Bucky could reach lower. He was absolutely sure that he had a blush a mile long over his cheeks but beneath him Steve lay as flushed as he would be on a hot summer day by the water. And, God, who was he to try and resist something as beautiful as this because of a little pink on his face.

Not wasting any more time, now that he knew better what he had to do, Bucky wrapped one hand around Steve and let the other touch gently below, feeling the warm slick from Steve's leaking hole. He got a whiff of the stuff when he gathered some up on two fingers before bringing them to his lips.

“Bucky, damn it, _Bucky,_ ” Steve groaned, looking at him and reaching out to touch whatever part of him he could. He needed more and he needed it like yesterday, and here was Bucky wanting to _taste_ him when all Steve wanted was his—

His train of thought was cut off entirely as he moaned loudly, the two fingers Bucky'd had in his mouth now pushing up to his ass and _inside_.

The look on Bucky's face was of unadulterated awe. He watched where his fingers disappeared into the tight heat of Steve's body, pulling them out then pushing in again. Bucky could feel Steve, every motion he made, every twitch and clench, all from inside of his body.

“Oh, God,” Bucky said brokenly. His gaze darted up to look at Steve. With his eyes screwed shut and his mouth open, panting and moaning with every exhale, Steve looked positively radiant.

Then Steve cried softly, “Please, more, damn it, I need more.”

Bucky worked his dick as best he could while also thrusting his fingers hard and deep, adding a third when Steve begged wordlessly. Finally, Bucky couldn't take it anymore, and he took his hands back. He gripped one of Steve's thighs tight and took his own cock in hand, rubbing his head against the wetness Steve was dripping with.

“Stevie, ah hell. Stevie I'm gonna—I'm gonna put it in,” Bucky tried to say coherently. Truly, he felt drunk with Steve's scent and _want_ and how unbelievably hard he was.

Steve just moaned, past the point of lucidity. When the press of Bucky's dick against him was finally enough to breach, Steve reached out blindly until he could wrap his arms around Bucky's shoulders. Bucky moved slowly, even though everything in his body was telling him to just go fast and hard and completely _ruin_ Steve.

Still, when he was fully inside of Steve as far as he could go, he kissed him hard, covering up the constant stream of whimpers and cries that Steve was letting out. He could feel Steve relaxing after some time, finally calming just enough that Bucky could pull out of him just a little, and push back in. He did this several times, further at each pull, until he was almost all the way out and thrust back in hard. Steve's body seized up in pleasure, holding onto Bucky so tightly that it was hard to move.

“Bucky, Bucky,” Steve breathed. “I need you, Bucky. Please, please.”

When Bucky pulled out again, his slam back in was followed by a guttural grunt. He couldn't help it. Something inside of him was telling him that this omega needed it hard and needed it fast. So he started up a rhythm, getting out of Steve's grasp enough that he could lean up and take Steve to pieces.

“God, yes.” The sounds leaving Steve now were barely human. “Fuck me, Bucky, fuck me. Oh, God.”

The words, the swears and curses leaving such a pure and untainted mouth were all Bucky needed. He fucked into his omega, his Steve, with abandon. He didn't even care, didn't even stop to think that the neighbors would surely hear them or that Sarah would be returning home at some point after she was finished with work.

Nothing mattered but his cock in Steve's ass and the powerful, incredible feelings that came with it. At some point, he felt Steve lock up and spill between their bodies, but he couldn't stop. Not when Steve was begging him so prettily to keep going. To keep fucking him until _something_ happened. He wasn't sure what that something was, but he'd know it when it came, he was sure.

After all, nothing had ever mattered more to him than Steve.

Steve, who was currently collapsed on his bed, arms above his head as Bucky took care of him. Steve, who was whining and pleading, ecstasy written on his body, on his skin. Steve, who Bucky loved more than anyone in the world. Steve, who, since the mandatory health class when he was thirteen, had been the only one that Bucky could ever dream of mating with. Steve. Just Steve. Always Steve.

The heat was roaring in Steve's veins, like a caged animal just waiting for release. He could barely feel himself anymore, was barely even in his own head. When he opened his eyes, all he could see was Bucky. And when he closed them again, all he saw was Bucky.

“Please, please,” Steve was whispering like a mantra, like it was the only word he knew besides Bucky's name. He felt heat searing through him as he came again, body relaxing even further once the spasms were over.

Bucky couldn't take it. He felt the change in Steve's body. He groaned and buried his face into Steve's neck as he thrust in just a few more times before he felt the sweet bliss of relief. He knew he was filling up Steve's hole, mixing his come with the delicious slick he was still producing.

And Steve still smelled amazing, more pungent now than before. As Bucky's nose pressed against the sweaty skin of Steve's neck, he opened his mouth to lick up the taste. He didn't realize what he was doing until Steve was yelping below him and trying to push him off. The tangy and cloying taste of blood hit Bucky's tongue.

“Bucky? Bucky, stop!” Steve croaked, throat sore and now with a burning, throbbing pain in the side of his neck. “You're hurting me!”

As Bucky pulled back, his head started clearing from the fog he'd been in. Bucky looked at the mark he had made, teeth indentations on Steve's skin even where he wasn't bleeding.

“Oh no,” he whispered, horrified. “Oh, shit. Steve, I'm sorry, I didn't mean to, I swear it.”

Steve just pushed at him until Bucky removed himself from his insides and sat back. The blond reached a hand up to touch the bite and then looked at the blood staining his fingers. “You . . .”

“I'm sorry, I'm sorry,” Bucky told him, wide-eyed and trying to comfort Steve with his hands, rubbing at his skin soothingly.

“Does this mean we're . . . mated?” Steve asked, his voice small. He had pulled up his knees, and sat with his legs folded. Bucky stopped short as Steve looked pointedly down and away from him.

“I-I don't know, Stevie. I didn't mean to do it, you gotta believe me.”

Steve still didn't look relieved at all. “I believe you, Buck.”

The miserable tone threw Bucky off. He had really, mucked things up, hadn't he? He was supposed to be helping his best friend through his first heat and instead he went and tried to mate the guy without even asking. He didn't know if it would take, anyway, or if betas like him could even mate with an omega.

“We'll try to find a way to get rid of it,” Steve said. “So you won't be stuck with me.”

Bucky blinked a few times. “Stuck with you.” he repeated slowly. “Stevie . . . I did that 'cause I _want_ you. I wanna be stuck with you. But I didn't even ask you, I didn't even—”

“You want to be?” Steve looked at him with wide, wet eyes. His bottom lip was kiss swollen and trembling.

“ _Yes_ you punk.” Bucky reached out to cup Steve's cheeks. Leaning forward, he kissed Steve just once before letting him go. “If you'll have me,” he added uncertainly.

For a long moment, Steve was silent. Then he said, “Buck, I don't want nobody else.”

Bucky could have cried with relief. As it was, he settled down in front of Steve, pulling him to his chest and holding onto him. Into his ear, Bucky whispered, “And I only ever wanted you, Stevie.”

They fell asleep like that, laid out bare beside each other.

. . .

When Steve's heat acted up again in the pre-dawn hours, Bucky gladly agreed for Steve to bite him, too, just to make it official.

Sarah left them breakfast and a note with congratulations at the door in the morning.

**Author's Note:**

> So like fic with betas hardly exist at all and I really like the idea of Bucky being a badass beta (wow alliteration) but also betas can mate so of course it makes sense to him that Steve would also be a beta but he is obviously not. I was trying to find info about mated pairs and there is very very little info about betas in general and absolutely nothing about if betas could potentially mate with omegas. However, I did see some things that pointed to betas only being able to impregnate other betas and not alphas or omegas. God I feel filthy but this is the first abo I've ever written so I wanted to know!


End file.
